Sinkhole risk in Lincoln County, SD: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock: 29%
At or near the surface: 0%
Buried under cover: 29%

What to do about a house in Lincoln County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 165 of Lincoln County's 577 square miles on soluble rock. With about 75,244 residents (130 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 337 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 29% under cover still counts, and how these percentages are measured.

Counties around Lincoln County

The nearest county rated sinkhole country is Knox County, NE, about 74 miles southwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Turner County, SD 22 mi west · 0% at surface
Lyon County, IA 27 mi east · 0% at surface
Minnehaha County, SD 27 mi north · 0% at surface
Clay County, SD 28 mi southwest · 0% at surface
Sioux County, IA 31 mi southeast · 0% at surface
Union County, SD 31 mi south · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Niobrara Formation (limestone), Late Cretaceous in age, covering about 29% of the county.

Against the rest of South Dakota

Lincoln County ranks 45 of 66 in South Dakota for soluble rock at the surface, and sits above 0% of US counties on that measure.